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We aim in this paper to propose a novel class of distributions that was created by merging the Topp-Leone distribution and the Generated families of Kumaraswamy and Marshall-Olkin. Its cumulative distribution function characterizes it and includes rational and polynomial functions. In particular, the following desirable properties of the new family are presented: Shannon entropy, order statistics, the quantile power series, and several associated measures and functions. Then, using a specific family member identified before, we create a parametric statistical model with the basic distribution being the inverse exponential distribution. Finally, a thorough investigation has been made to implement this new distribution with three data sets: the glass fibers data set, the glass Alumina data set and the hailing times data set. In comparison to six prominent competitors, the new model performs favorably on all statistical tests and criteria that were examined.
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In applied sectors, data modeling/analysis is very important for decision-making and future predictions. Data analysis in applied sectors mainly relies on probability distributions. Data arising from numerous sectors such as engineering-related fields have complex structures. For such kinds of data having complex structures, the implementation of classical distributions is not a suitable choice. Therefore, researchers often need to look for more flexible models that might have the capability of capturing a high degree of kurtosis and increasing the fitting power of the classical models. Taking motivation from the above theory, to achieve these goals, we study a new probabilistic model, which we named a new beta power flexible Weibull (NBPF-Weibull) distribution. We derive some of the main distributional properties of the NBPF-Weibull model. The estimators for the parameters of the NBPF-Weibull distribution are derived. The performances of these estimators are judged by incorporating a simulation study for different selected values of the parameters. Three data sets are used to demonstrate the applicability of the NBPF-Weibull model. The first data set is observed from sports. It represents the re-injury rate of various football players. While the other two data sets are observed from the reliability zone. By adopting certain diagnostic criteria, it is proven that the NBPF-Weibull model repeatedly surpasses well-known classical and modified models.
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In this article, we suggest an enhanced estimator for the estimation of finite population variance using twofold auxiliary variable under stratified random sampling. The numerical expressions for the bias and MSE are determined up to the first order of approximation. In order to effectively validate the theoretical findings, three actual data sets are included. Additionally, the application of the suggested estimators is demonstrated using a simulation study. Results of an empirical comparison among the suggested and existing estimators were investigated. To determine how good the suggested estimator, in comparison to the preliminary estimators, the MSE criterion is used. The suggested estimator has a smaller MSE and better PRE than existing estimators, according to numerical results utilizing actual data sets and a simulation analysis.
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This research presents a novel approach for cervical cancer detection and segmentation using tissue images with multiple cells. The study employs a novel deep learning architecture based on Mask Region-Based Convolutional Neural Network (RCNN) and statistical analysis. This new architecture enables us to achieve a high percentage of detection and pix-to-pix area segmentation. A mean Average Precision (mAP) higher than 60% for 3-class and 5-class was achieved. In addition, higher F1-scores of 70% for 3-class and 5-class were obtained. This investigation is a collaborative work, where a medical consultant collected the samples from the Papanicolaou (Pap) Smear examination and labeled the cells presented to the liquid-based cytology (LBC). Furthermore, the online available benchmark data set, SIPaKMeD, was also utilized. Additionally, sample images from the Mendeley data set were also labeled by the trained medical consultant for comparison. The proposed scheme automatically generates a full report for a medical consultant to identify the location of the malicious cells in the given images and expedite the diagnosis and treatment process.
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When measuring the research variable is complicated, expensive, or problematic, median ranked set sampling (MRSS) is often utilized since it is straightforward to rank the components using a low-cost sorting criterion. Using this sampling scheme, many authors considered the problem of population mean estimation with a single auxiliary variable in order to obtain more precised estimators than the traditional ratio type regression estimators. In this article, we extend their ideas based on regression approach using two auxiliary variables and introduce a new regression-type estimator along with its theoretical expression of minimum mean square error (MSE). The suggested estimator's applicability is demonstrated using both simulated and real-world data sets.
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This article discusses the problem of estimation with step stress partially accelerated life tests using Type-II progressively censored samples. The lifetime of items under use condition follows the two-parameters inverted Kumaraswamy distribution. The maximum likelihood estimates for the unknown parameters are computed numerically. Using the property of asymptotic distributions for maximum likelihood estimation, we constructed asymptotic interval estimates. The Bayes procedure is used to calculate estimates of the unknown parameters from symmetrical and asymmetric loss functions. The Bayes estimates cannot be obtained explicitly, therefor the Lindley's approximation and the Markov chain Monte Carlo technique are used to obtaining the Bayes estimates. Furthermore, the highest posterior density credible intervals for the unknown parameters are calculated. An example is presented to illustrate the methods of inference. Finally, a numerical example of March precipitation (in inches) in Minneapolis failure times in the real world is provided to illustrate how the approaches will perform in practice.
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In real-life experiments, collecting complete data is time-, finance-, and resources-consuming as stated by statisticians and analysts. Their goal was to compromise between the total time of testing, the number of units under scrutiny, and the expenditures paid through a censoring scheme. Comparing failure-censored schemes (Type-â ¡ and Progressive Type-â ¡) to Time-censored schemes (Type-â ), it's worth noting that the former is time-consuming and is no more suitable to be applied in real-life situations. This is the reason why the Type-â adaptive progressive hybrid censoring scheme has exceeded other failure-censored types; Time-censored types enable analysts to accomplish their trials and experiments in a shorter time and with higher efficiency. In this paper, the parameters of the inverse Weibull distribution are estimated under the Type-â adaptive progressive hybrid censoring scheme (Type-â APHCS) based on competing risks data. The model parameters are estimated using maximum likelihood estimation and Bayesian estimation methods. Further, we examine the asymptotic confidence intervals and bootstrap confidence intervals for the unknown model parameters. Monte Carlo simulations are carried out to compare the performance of the suggested estimation methods under Type-â APHCS. Moreover, Markov Chain Monte Carlo by applying Metropolis-Hasting algorithm under the square error of loss function is used to compute Bayes estimates and related to the highest posterior density. Finally, two data sets are studied to illustrate the introduced methods of inference. Based on our results, we can conclude that the Bayesian estimation outperforms the maximum likelihood estimation for estimating the inverse Weibull parameters under Type-â APHCS.
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Teorema de Bayes , Simulación por Computador , Funciones de Verosimilitud , Cadenas de Markov , Método de MontecarloRESUMEN
PURPOSE: The objective was to evaluate the efficacy of a dentifrice containing Brazilian Red Propolis (BRP) against salivary Lactobacillus spp. and plaque formation. METHODS: This was a randomized, double-blind clinical trial. Forty-two participants were randomized into two groups according to the dentifrice employed: G1 (fluoridated BRP dentifrice) and G2 (fluoridated common dentifrice). Saliva was collected and the visible plaque index (VPI) was recorded at the baseline (D0) and 4 weeks after day 0 (D28). Microbiological analysis was performed using two dilutions. Lactobacillus spp. isolates were identified and their abundance was expressed as log (CFU/mL). RESULTS: For the first dilution, the counts of Lactobacillus spp. in G1 was 1.15 ± 0.41 at D0 and 0.68 ± 0.15 at D28 (P < 0.05) and in G2 it was 1.33 ± 0.52 at D0 and 1.84 ± 0.39 at D28 (P < 0.05). For the second dilution, the corresponding values in G1 and G2 were 0.87 ± 0.34 and 0.64 ± 0.37, respectively (P = 0.1547), and 1.54 ± 0.47 and 1.62 ± 0.37, respectively (P = 0.9999). The corresponding VPI values for G1 and G2 were 38.10 ± 17.95 and 20.60 ± 16.44, respectively (P < 0.05), and 38.38 ± 19.65 and 27.40 ± 14.63, respectively (P = 0.03). CONCLUSION: The dentifrice containing BRP showed antimicrobial activity against Lactobacillus spp. and decreased the VPI for up to 4 weeks.
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Placa Dental , Dentífricos , Gingivitis , Própolis , Índice de Placa Dental , Método Doble Ciego , HumanosRESUMEN
The quadratic rank transmutation map is used in this article to suggest a novel extension of the power inverted Topp-Leone distribution. The newly generated distribution is known as the transmuted power inverted Topp-Leone (TPITL) distribution. The power inverted Topp-Leone and the inverted Topp-Leone are included in the recommended distribution as specific models. Aspects of the offered model, including the quantile function, moments and incomplete moments, stochastic ordering, and various uncertainty measures, are all discussed. Plans for acceptance sampling are created for the TPITL model with the assumption that the life test will end at a specific time. The median lifetime of the TPITL distribution with the chosen variables is the truncation time. The smallest sample size is required to obtain the stated life test under a certain consumer's risk. Five conventional estimation techniques, including maximum likelihood, least squares, weighted least squares, maximum product of spacing, and Cramer-von Mises, are used to assess the characteristics of TPITL distribution. A rigorous Monte Carlo simulation study is used to evaluate the effectiveness of these estimators. To determine how well the most recent model handled data modeling, we tested it on a range of datasets. The simulation results demonstrated that, in most cases, the maximum likelihood estimates had the smallest mean squared errors among all other estimates. In some cases, the Cramer-von Mises estimates performed better than others. Finally, we observed that precision measures decrease for all estimation techniques when the sample size increases, indicating that all estimation approaches are consistent. Through two real data analyses, the suggested model's validity and adaptability are contrasted with those of other models, including the power inverted Topp-Leone, log-normal, Weibull, generalized exponential, generalized inverse exponential, inverse Weibull, inverse gamma, and extended inverse exponential distributions.
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Funciones de Verosimilitud , Simulación por Computador , Análisis de los Mínimos Cuadrados , Método de Montecarlo , IncertidumbreRESUMEN
Introduction Several minimally invasive spine approaches and techniques have been developed in recent years. While the disease processes affecting the spinal motion segment have remained largely the same, the emerging technologies have changed treatment options radically and not necessarily in an organized fashion. The current diagnostic techniques, also evolving, have helped us appreciate the disease's pathoanatomy in minute details. A comprehensive classification method accounting for all anatomical variations in the disc disease, tailored to treatment options, is necessary. Such a classification will allow the surgeon to choose an appropriate surgical option in a consistent fashion. We feel that our classification system will help the spine surgeon make that important decision consistently, with minimal risk of leaving behind a significant lesion or disrupting an otherwise normal structure of the spinal motion segment. Furthermore, we feel such a comprehensive classification will help surgeons and other caregivers to standardize treatment approaches to the various presentations of disc disease, and apply the evolving technology in an organized fashion. Purpose To develop a comprehensive, treatment-orientated classification of the lumbar disc disease. Materials and Methods The literature was reviewed for the classification of disc disease. The morphology of the disc disease, the topography of the disc lesion, and the symptom-complex produced by the disc lesion are identified and graded. The features so identified and graded are placed in a matrix. The combinations of the anatomical features and symptoms are then computed as shown in the matrix. The MRI database held in the office was studied to determine the most frequent combinations of the disc disease and symptom complex. Results A total of 494 combinations were identified, but most have no clinical relevance. The retrospective study of the clinical data and MRI studies of 93 patients (50 male and 43 female) revealed the most affected motion-segment was L5-S1 (male = 19.3%, and female = 23.8%). The most common patho-anatomy is a globally bulging disc (T3L1), representing 37.6% of the total. The second most common combination is a degenerated disc with central, intra-annular tear T4L1), representing 20.4% of the total. At 11.8%, globally bulging with severe axial pain and moderate radicular pain represented the most common patho-anatomic/clinical classification (T3L1B4R2). The most frequent top 10 patho-anatomic/clinical classifications represented 15.5% of the total. Conclusion In light of the multiple surgical options for excision of the herniated lumbar disc, including the conventional and minimally invasive, and the fact that the imaging technology allows spine surgeons to see in great detail, the disease status of each of the components of the spinal motion segment, it is imperative to develop comprehensive classification systems which take account of the unique characteristics of the disease entity and guide treatment strategies. The classification system presented here is fairly complex, but the software technology will be utilized for the classification system along with the most appropriate treatment approach.
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Context:Lacrimal drainage system obstruction gives discomfort to patients and threatens intraocular surgeries by infection, thus, knowledge of its bacteriology leads to the choice of effective therapy.Aim:To determine the bacteriology of nasolacrimal duct obstruction in an adult Libyan patient population and to analyze the appropriate antimicrobial therapy based on susceptibility testing.Settings and Design:A prospective study was conducted at the Great River Eye hospital, Benghazi/Libya in the period between September 2005 and February 2007.Methods:Lacrimal swab materials collected from patients aged 1862 years who were diagnosed as having lacrimal passage obstruction and referred for lacrimal drainage surgery. The specimens were cultured and results analyzed.Results:Of 86 cases, 87.2% yielded a positive culture result. The majority of microorganisms were gram positive bacteria (73.3%) with Staphylococcus Aureus being the most frequently cultured species (36%) of the sample. Gram negative bacteria represented 26.7% of the isolates. The most common gram negative bacteria were Pseudomonas, Klebsiella, and E. coli which were isolated in 8% of the cases each. Staphylococcus aureus was isolated from 28.6% of cases having epiphora with no clinical signs of lacrimal drainage system infection. Ciprofloxacin (96%) and Gentamycin (94.7%) were found to be the most sensitive antibiotics against isolated organisms.Conclusions:Adult patients with lacrimal drainage system obstruction harbor microorganisms in their lacrimal sacs indicating the importance of investigating patients before planning for intraocular surgeries and considering prophylactic use of antibiotics before lacrimal drainage procedures
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Drenaje , Obstrucción del Conducto Lagrimal/microbiología , Libia , Pruebas de Sensibilidad MicrobianaRESUMEN
Malakoplakia is a rare chronic granulomatous disease that may affect many organs, including the lung, brain, adrenal glands, pancreas, bone, and the genitourinary tract. The gastrointestinal tract is the most common site of involvement outside of the urinary tract. Herein, we present a case of a 65-year-old male who presented with abdominal pain and unintentional weight loss. Physical examination findings were unremarkable, but colonoscopy revealed an isolated large, flat, soft, and pale lesion in the transverse colon. Histopathological examination of the lesion showed expansion of the lamina propria due to numerous lymphocytes, plasma cells, neutrophils, and polygonal cells. Von Kossa stain showed small intracytoplasmic basophilic granular inclusions, and these histiocyte cells showed numerous Michaelis-Gutmann bodies, findings considered as diagnostic features of colonic malakoplakia. This is a rare case of isolated malakoplakia of the transverse colon diagnosed on endoscopic specimens. The majority of reported cases have shown an association between systemic diseases and colorectal adenocarcinoma. In addition, most reported cases of colonic involvement have been in the rectum, sigmoid, and right colon.
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The study was done to investigate osteoporosis prevalence in 275 hip fracture admissions at the Trauma Unit of Assiut University Hospitals and associated factors, which are understudied in our locality. Prevalence was 74.9%. Female sex, older age, low body mass index, and fall on the ground were associated with osteoporosis. PURPOSE: This study aims to identify osteoporosis prevalence in hip fracture admissions at the Trauma Unit of Assiut University Hospitals and to study the independent correlates of osteoporosis-related fracture. METHODS: A prospective cross-sectional study was carried out in 275 hip fracture patients admitted to the Trauma Unit of Assiut University Hospitals from January through December 2014 of both sexes aged 50 years and older. Exclusion criteria were polytrauma, major accidents, and history of chronic conditions and long-term medication associated with osteoporosis risk increase and bilateral hip fractures. For every patient, weight, height, and bone mineral density by dual-energy x-ray absorptiometry (DEXA) were recorded. Tests of significance for non-parametric data were used. The questionnaire included sociodemographic characteristics, dietary habits, lifestyle factors such as smoking and physical activity, and female obstetric and gynecological factors. RESULTS: Mean age was 70.82 ± 11.02 SD; 51.6% were males and 8.4% were obese. Fall on ground was in 81.1% of fractures. Osteoporosis (femoral neck T score ≤ -2.5 SD) prevalence was 74.9%. By univariable analysis, significant correlates were female gender, older age, normal BMI, and fall on the ground. Milk and cheese daily intake was significantly associated with lower prevalence of osteoporosis. In a multivariable logistic regression model, female sex, older age, low BMI, and fall on the ground were associated with osteoporosis. CONCLUSIONS: Osteoporosis prevalence is high among hip fracture patients and associated with female sex, increase in age, low BMI, and fall on ground. Strategies to prevent osteoporosis are needed to decrease hip fracture rates.
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Fracturas de Cadera , Osteoporosis , Fracturas Osteoporóticas , Absorciometría de Fotón/métodos , Accidentes por Caídas , Anciano , Anciano de 80 o más Años , Índice de Masa Corporal , Densidad Ósea , Estudios Transversales , Egipto/epidemiología , Ejercicio Físico , Femenino , Fracturas de Cadera/epidemiología , Fracturas de Cadera/etiología , Fracturas de Cadera/terapia , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Osteoporosis/complicaciones , Osteoporosis/diagnóstico , Osteoporosis/epidemiología , Fracturas Osteoporóticas/epidemiología , Fracturas Osteoporóticas/terapia , Prevalencia , Factores de RiesgoRESUMEN
BACKGROUND: The lumbosacral junction is a difficult area for spine surgery because of the complex anatomy. In the era of minimally invasive spine surgery, the presence of the iliac wing has, at the level of lumbosacral junction, created a major obstacle in the paths of two of the major approaches, namely, the direct lateral and percutaneous posterolateral endoscopic approaches. A trans-iliac cadaver study published by the senior author and co-workers in 1997, suggested the possibility of an alternative approach to the lumbosacral junction. PURPOSE: To determine the feasibility of percutaneous, endoscopic trans-iliac approach to the L5-S1 disc and foramen. STUDY DESIGN: Prospective case series study. MATERIALS AND METHODS: 15 consecutive patients undergoing the transiliac approach to L5-S1 disc and foramen were included in the study. Pre- and postoperative visual analogue scale (VAS); Oswestry Disability Index (ODI); and intra-operative blood loss and operative time, were obtained for the study. Preoperative MRI or CT scan was used to determine the need for trans-iliac access. The procedure was performed with the patient in prone position and under monitored sedation for decompression. Endotracheal anesthesia was used for fusion cases. The transiliac access was established with a cannulated drill or core drill through the iliac wing. Once the trans-iliac window had been created, the rest of the procedure proceeded as for percutaneous endoscopic transforaminal decompression and fusion. RESULTS: 15 patients (9 male and 6 female) participated in the study. The VAS for back and leg pain significantly improved in all patients. The ODI dropped by more than 50%. There was minimal blood loss, and transient post-operative dysesthesia in 2 cases which resolved after 3 weeks. CONCLUSION: Endoscopic trans-iliac approach to the L5-S1 disc and foramen is feasible and safe. Decompression can be performed safely via trans-iliac access with minimal blood loss, and in a short operative time.
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OBJECTIVE: To perform a critical comparison between the Brazilian national essential medicines list (Rename, 2012) with the list of essential medicines for children (LEMC, 2011) of the World Health Organization (WHO), regarding the differences among drugs and formulations listed for children. METHODS: The LEMC drugs were classified into four categories: 1) absent in Rename; 2) included in Rename but without any formulation suitable for children; 3) listed in Rename only in some formulations; 4) present in Rename in all formulations. The missing formulations were analyzed by therapeutic group. Alternatives present in Rename were searched. RESULTS: From the 261 drugs of interest on the LEMC, 30.3% are absent from Rename, 11.1% are in Rename but without any pediatric formulation, and 32.2% are present in some but not all formulations listed in LEMC. Considering all formulations items listed in the LEMC (n = 577), 349 are missing from Rename, of these 19.6% due to their strength, and 18.5% due to the the dosage form. Useful formulations specific for neonatal care, respiratory tract, central nervous system, and anti-infectives, among other groups, are missing. CONCLUSION: The lack of age-appropriate formulations of essential medicines for children in Brazil includes important therapeutic groups and indispensable drugs for severe clinical conditions. Some of these products exist in the Brazilian pharmaceutical market, but not in public facilities; others could be produced by national laboratories with commercial interest or stimulated by a specific governmental policy, as in other countries.
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Anticonvulsivantes/provisión & distribución , Antifúngicos/provisión & distribución , Antivirales/provisión & distribución , Broncodilatadores/provisión & distribución , Medicamentos Esenciales/provisión & distribución , Accesibilidad a los Servicios de Salud/legislación & jurisprudencia , Brasil , Niño , Medicamentos Esenciales/clasificación , Política de Salud/legislación & jurisprudencia , Humanos , Organización Mundial de la SaludRESUMEN
OBJECTIVE: To perform a critical comparison between the Brazilian national essential medicines list (Rename, 2012) with the list of essential medicines for children (LEMC, 2011) of the World Health Organization (WHO), regarding the differences among drugs and formulations listed for children. METHODS: The LEMC drugs were classified into four categories: 1) absent in Rename; 2) included in Rename but without any formulation suitable for children; 3) listed in Rename only in some formulations; 4) present in Rename in all formulations. The missing formulations were analyzed by therapeutic group. Alternatives present in Rename were searched. RESULTS: From the 261 drugs of interest on the LEMC, 30.3% are absent from Rename, 11.1% are in Rename but without any pediatric formulation, and 32.2% are present in some but not all formulations listed in LEMC. Considering all formulations items listed in the LEMC (n = 577), 349 are missing from Rename, of these 19.6% due to their strength, and 18.5% due to the the dosage form. Useful formulations specific for neonatal care, respiratory tract, central nervous system, and anti-infectives, among other groups, are missing. CONCLUSIONS: The lack of age-appropriate formulations of essential medicines for children in Brazil includes important therapeutic groups and indispensable drugs for severe clinical conditions. Some of these products exist in the Brazilian pharmaceutical market, but not in public facilities; others could be produced by national laboratories with commercial interest or stimulated by a specific governmental policy, as in other countries.
OBJETIVO: Realizar uma comparação crítica entre a Relação Nacional de Medicamentos Essenciais (Rename, 2012) e a Lista de Medicamentos Essenciais para Crianças (LMEC, 2011) da Organização Mundial de Saúde (OMS), com relação às diferenças entre os medicamentos e as formulações listadas para crianças. MÉTODOS: Os medicamentos da LMEC foram classificados em quatro grupos: 1) não constam na Rename; 2) constam na Rename, porém sem qualquer formulação adequada para crianças; 3) listados na Rename apenas com algumas formulações; 4) constam na Rename em todas as formulações. As formulações que faltam foram analisadas por grupos terapêuticos. As alternativas presentes na Rename foram pesquisadas. RESULTADOS: Dos 261 medicamentos de interesse listados na LMEC, 30,3% não estão presentes na Rename, 11,1% estão na Rename, mas sem qualquer formulação pediátrica, e 32,3% estão presentes em algumas, mas não todas as formulações listadas na LMEC. Considerando todos os itens de formulações listados na LMEC (n = 577), 349 não constam na Rename, desses, 19,6% devido à intensidade de dosagem, e 18,5% devido à forma farmacêutica. Faltam formulações úteis específicas para cuidado neonatal, trato respiratório e sistema nervoso central, anti-infecciosos, entre outros grupos. CONCLUSÃO: A ausência de formulações adequadas à idade de medicamentos essenciais para crianças no Brasil inclui importantes grupos terapêuticos e medicamentos indispensáveis para quadros clínicos graves. Alguns desses produtos são encontrados no mercado farmacêutico brasileiro, porém não existem em unidades públicas; outros poderiam ser produzidos por laboratórios nacionais com interesse comercial ou estimulados por uma política governamental específica, como é feito em outros países.
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Niño , Humanos , Anticonvulsivantes/provisión & distribución , Antifúngicos/provisión & distribución , Antivirales/provisión & distribución , Broncodilatadores/provisión & distribución , Medicamentos Esenciales/provisión & distribución , Accesibilidad a los Servicios de Salud/legislación & jurisprudencia , Brasil , Medicamentos Esenciales/clasificación , Política de Salud/legislación & jurisprudencia , Organización Mundial de la SaludRESUMEN
Bixa orellana L., urucum, or urucu, a native tropical tree of Central and South American rain forests is used to treat various diseases in popular medicine. In Ceará, Northeast of Brazil, the seeds of urucum have been used for the treatment of high lipid blood levels. The present study investigated the effects of the aqueous extract from Bixa orellana seeds (AEBO) in mice with hyperlipidemia induced by tyloxapol, fructose and ethanol. In hyperlipidemia induced by Triton WR1339, 400 and 800 mg/kg AEBO reduced triglycerides (TG) serum levels at 24 h and 48 h. In the study of hypertriglyceridemia induced by fructose, AEBO in doses of 400 mg/kg and 800 mg/kg reduced TG levels by 48.2% and 48.7%, respectively. Finally, the ethanol experimental model with 400 mg/kg AEBO promoted a reduction of 33.6% of TG levels, while the 800 mg/kg concentration reduced hypertriglyceridemia in 62.2%. In conclusion, the aqueous extract of the seeds of Bixa orellana was capable of reversing the hypertriglyceridemia induced by Triton, fructose and ethanol, demonstrating a hypolipidemic effect. However, further studies are necessary to discover the precise mechanism of action.
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Bixaceae/química , Hiperlipidemias/tratamiento farmacológico , Hipertrigliceridemia/tratamiento farmacológico , Extractos Vegetales/farmacología , Animales , Hiperlipidemias/inducido químicamente , Hipertrigliceridemia/inducido químicamente , Masculino , Ratones , Semillas/química , Triglicéridos/sangreRESUMEN
The aim of the present study was to investigate the production of tetragonal zirconia (t-ZrO(2)) particles (experimental t-ZrO(2)) from monoclinic zirconia (m-ZrO(2)) and to evaluate the effect of the t-ZrO(2) content on the fracture toughness of alumina-zirconia composites by conducting ASTM E399 standard test. In the laboratory study, t-ZrO(2) powder was produced by heat treating m-ZrO(2) containing 10wt.% MgO. Alumina and alumina-zirconia composite powders containing various types and amounts of m-ZrO(2) and t-ZrO(2) were prepared (0-20 wt.%), shaped by slip casting to achieve a uniform distribution and homogeneous microstructure in accordance with the dimensions of ASTM E399 standards, dried, sintered at three different temperatures: 1400, 1500 and 1600 °C for two hours, and characterized. The results of the XRD analysis showed that t-ZrO(2) was produced at 1400 °C. In t-ZrO(2)-doped alumina composites, t-ZrO(2) partially transformed to m-ZrO(2) after sintering, whereas commercial t-ZrO(2) (Tosoh TZ-3Y) remained intact. SEM studies on samples sintered at 1600 °C revealed that the addition of zirconia inhibited abnormal grain growth of alumina, leading to a homogeneous and equiaxed grain structure, especially at high concentrations of zirconia. ZrO(2)-doping enhanced the fracture toughness of the composites, which increased with an increase in the t-ZrO(2) content. The maximum fracture toughness was 11.5 MPam(1/2) and was observed when the t-ZrO(2) content was equal to 20 wt.%. Alternatively, the maximum fracture toughness for pure alumina was 5.9 MPam(1/2).
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Óxido de Aluminio/química , Materiales Dentales/química , Óxido de Magnesio/química , Fenómenos Mecánicos , Microtecnología/métodos , Circonio/química , Dureza , Ensayo de MaterialesRESUMEN
BACKGROUND: The standard approach to the thoracic disc is through thoracotomy. The video-assisted thoracoscopic approach has been used as an alternative to the open approach for nearly 20 years, and more recently, extracavitary, posterolateral approaches have been introduced. Both the transthoracic procedures involve deflating the lung for access to the spine, and postoperative thoracic drainage is necessary; postoperative morbidity can be significant. The retropleural procedures are in their infancy, but the published results are promising. The purpose of this study is to introduce the posterolateral arthroscopic thoracic decompression and fusion procedure, which is extrapleural, less disruptive to normal anatomy, and cost-effective. METHODS: Fifteen consecutive patients who underwent arthroscopic decompression and interbody fusion of the thoracic spine were prospectively studied according to the hospital's institutional review board protocol. The Short Form 36 and visual analog scale questionnaires were completed preoperatively and postoperatively. Paired t tests were used for statistical analysis. The patient was placed in the prone position on a radiolucent table, and instrumentation was performed under fluoroscopic control. Two portals were developed ipsilaterally (one for the arthroscope and the other for instruments) on the side of disc herniation, and a single portal was used on the contralateral side. Various instruments were used for disc excision and exploration of the spinal canal. Fusion was accomplished with bilateral corticocancellous dowels obtained from the iliac crests. Infiltration of the access channel and facet injections of the contiguous joints were performed with bupivacaine, for immediate postoperative pain control. RESULTS: Fifteen patients with a mean age of 54 years were followed up for 28 months postoperatively. The overall back pain score decreased from 7.2 (SD, 1.5) to 3 (SD, 2) after the procedure (P < .005). Eleven patients were satisfied with their current lifestyle postoperatively as opposed to one preoperatively. Two patients had reoccurrences. Hospital stay averaged 18.5 hours. The operating room cost and the cost of hospital stay was 51.9% of the cost of anterior open discectomy. CONCLUSIONS: The extrapleural, biportal, ipsilateral arthroscopic approach for the decompression and interbody fusion of the thoracic spine is feasible, cost-effective, less traumatic, and associated with minimal complications. The best results were obtained in patients with single-level thoracic disc herniation. The technique is applicable for most thoracic disc herniations.
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BACKGROUND: On the basis of the experiences gained from conventional open spinal procedures, a long list of desirable objectives have emerged with the evolution of the lesser invasive spinal procedures. At the top of that list is the desire to minimize the trauma of surgery. The rest of the objectives, which include reductions of operating time, surgical blood loss, hospital stay, postoperative narcotic medication, convalescence, complication rates, and escalating health care costs, as well as the desire of elderly patients to continue rigorous physical activities, largely depend on the ability to minimize the trauma of surgery. The purpose of this study was to investigate the feasibility of the least invasive lumbar decompression, interbody fusion and percutaneous pedicle screw implantation, to minimize surgical trauma without compromising the quality of the treatment outcome, as well as to minimize risk of complications. METHODS: In this case series, 60 patients with diagnoses of degenerative disc disease, degenerative motion segments with stenosis, and spondylolisthesis, in whom nonoperative treatments failed, were treated with endoscopic transforaminal decompression and interbody fusion by 1 surgeon in 2 centers. The outcome measures were as follows: operating time, intraoperative blood loss, hospital stay, Visual Analogue Scale (VAS) scores for back and leg pain, scores on the Roland-Morris Disability Questionnaire, and postoperative imaging studies. A consecutive series of patients who met the treatment criteria completed VAS forms and Roland-Morris questionnaires preoperatively. Surgical procedures included arthroscopic decompression of the foramina and the discs; endplate preparation and implantation of allograft bone chips and bone morphogenetic protein 2 on absorbable collagen sponge into the disc space; and percutaneous implantation of pedicle screws. Postoperatively, the patients again completed the VAS forms and Roland-Morris questionnaires. Their charts were reviewed for office notes, operative notes, hospital stay, medications, and imaging studies. The latest X-ray and computed tomography scan films were reviewed and analyzed. Patients were followed up for a minimum of 6 months. The literature was reviewed for comparison of outcomes. RESULTS: Sixty patients met the inclusion criteria. The mean age was 52.8 years. The duration of illness averaged 5 years. Follow-up ranged from 6 to 25 months, with a mean of 12 months. Preoperative diagnoses included degenerative disc disease, degenerative motion segments with stenosis, and spondylolisthesis. The mean time in the operating room was 2 hours 54 minutes. Estimated blood loss averaged 57.6 mL. The duration of the hospital stay averaged 2.6 days. Preoperative back pain and leg pain were significantly reduced (P < .005). Forty-seven imaging studies obtained at the last visit, including X-ray and computed tomography scans, showed solid fusion in 28 patients (59.6%), stable fixation in 17 (36.2%), and osteolysis around the pedicle screws in 2 (4.2%). All patients had improvement of motor function, whereas 2 patients complained of residual numbness. In addition, 8 patients (13%) complained of residual discomfort on extension of the lumbar spine. Two patients had pedicle screw-related complications requiring surgery. A review of the literature showed that endoscopic transforaminal decompression and interbody fusion performed better than open transforaminal lumbar interbody fusion/posterior lumbar interbody fusion, minimally invasive transforaminal lumbar interbody fusion, and extreme lateral lumbar interbody fusion, with regard to most parameters studied. CONCLUSIONS: The endoscopic transforaminal lumbar decompression, interbody fusion, and percutaneous pedicle screw instrumentation consistently produced satisfactory results in all demographics. It performed better than the alternative procedures for most parameters studied.